More than a consultant. A trusted advisor.

Established in 1961, Netherland, Sewell & Associates, Inc. (NSAI) is a worldwide leader of petroleum property analysis for industry and financial organizations and government agencies. With offices in Dallas and Houston, we deliver high-quality, fully-integrated engineering, operational, geological, geophysical, petrophysical, and economic solutions for all facets of the upstream energy industry.

The #1 Choice for SEC Reserves Reporting

An NSAI report honors all the data and industry reserves definitions to give a full and fair inventory of reserves and cash flow. Each report is based on sound judgment, broad experience, technical expertise, and accepted practices.


Each year, NSAI conducts its highly regarded Oil & Gas Property Evaluation Seminar in multiple locations for non-technical financial professionals whose work relates to the petroleum industry. Our panel of in-house experts will help you gain a better understanding of reserves evaluations and reports.


NSAI has compiled numerous resources in developing its procedures and standards for reserves reports to be used in filings with the SEC, including pricing data (compiled monthly) and guidance. More companies use NSAI for their SEC reporting needs than any other petroleum consulting firm.

A Global Reach


Netherland, Sewell & Associates, Inc. is one of the most respected names in independent reserves reporting. Our technical staff has successfully completed thousands of challenging assignments for leading petroleum and financial concerns around the globe. Our clients include small privately owned oil and gas companies, major and independent oil and gas companies, national oil and gas companies, financial institutions, and investors. A few of the companies familiar with our work are shown below.

Ithaca Energy logo
JP Morgan Chase & Co. logo
Talos Energy logo
Shell logo
Ovintiv logo
Hilcorp logo
ExxonMobil logo
Chord Energy logo
EQT logo
BP logo
Aethon logo
Bank of America logo
Woodside Energy logo
Endeavor Energy Resources logo
EIG logo
Mubadala Energy logo
Chesapeake Energy logo
Kayne Anderson Capital Advisors logo
W&T Offshore logo
Santos logo
Perenco logo
Comstock Resources logo
Diversified Energy logo
Pioneer Natural Resources logo
Range Resources logo